Magnetocaloric effect in high Gd content Gd-Fe-Al based amorphous/nanocrystalline systems with enhanced Curie temperature and refrigeration capacity

Linlin Zhang,Mingdong Bao,Qiang Zheng,Juan Du,Linhai Tian

doi:10.1063/1.4945407

Abstract

The Gd-Fe-Al amorphous/nanocrystalline composites were successfully designed and obtained with both high Curie temperature (Tc) and large magnetic entropy change (ΔSM). The Tc can be tuned from 172 to 280 K and refrigeration capacity (RC) has a value between 690 and 867 J/kg under a field change of 0–5 T by changing the Gd contents and the formation of Gd nanocrystallites. And, ΔSM in Gd-Fe-Al amorphous/nanocrystalline composites reached a value of 7.2 J kg−1 K−1 under a field change of 0–5 T. The high RC in Gd-Fe-Al system were ascribed to the widening full width at half maximum (δFWHM) up to 240 K of the magnetic entropy change (ΔSMmax) peak because of the combination contribution of amorphous matrix and the precipitated Gd-riched nanocrystalline. Our research would shed light on how to design attractive candidates for magnetic refrigeration materials with high performance at near room temperature.

Highlights

Magnetic refrigeration based on magnetocaloric effect (MCE) has attracted increasing attention because of its superior properties, such as high energy efficiency and environmental friendliness
The large MCE has been extensively studied on various crystalline materials with a first-order magnetic transition, such as La(Fe1−x, Six)[13,2,3] Gd5Si2Ge2,4 MnFe(P,As),[5] Ni-Mn-X (X = Sn, In, Sb),[6,7,8] etc
The magnetic properties were measured by superconducting quantum interference device magnetometer (SQUID)

Summary

INTRODUCTION

Magnetic refrigeration based on magnetocaloric effect (MCE) has attracted increasing attention because of its superior properties, such as high energy efficiency and environmental friendliness. Have some unique properties that are superior to those of crystalline alloys, such as, no thermal and field hysteresis, large electrical resistivity, high corrosion resistance, tailorable magnetic transition temperature, fine molding and processing behavior. These characteristics are technically important for the use of amorphous materials as more suitable candidates in magnetic refrigeration applications. The negative point of amorphous materials is their lower Curie temperatures and lower magnetic entropy change compared to those of their crystalline counterparts, which are important factors need to be solved before their real application as refrigeration materials at room temperature. The reason of high Curie temperature and large magnetic entropy change was discussed and explained

EXPERIMENTAL

RESULTS AND DISCUSSIONS

CONCLUSIONS